Label heating device



July 9, 1963 H. A. TREADWELL LABEL HEATING DEVICE File d Aug. 8, 1962 2 SheetsSheet 1 July 9, 1963 H. A. TREADWELL LABEL HEATING DEVICE 2 Sheets-Sheet 2 Filed Aug. 8, 1962 United States Patent 3,097,234 LABEL HEATlNG DEVICE Harold A. Treadwell, 156 Glenhill Drive, Rochester 18, N.Y. Filed Aug. 8, 1962, Ser. No. 215,671 2 Claims. (Cl. 219-19) This invention relates to a label heating device [for thermo-activated adhesive coated labels used on plastic wrapped packages of various types.

An object of the invention is to provide a device for sensitizing or activating heat sensitive labels having a label supporting member provided with a label positioning means to properly locate the label on the member for activating the desired area of the adhesive on the label.

Another object of the invention is to provide a heating device for thermo-activated adhesive coated labels in which a heat conductive member for supporting the label to be activated is constructed to provide inner and outer heat zones arranged to have the outer heat zone heated to a lower degree of heat than the inner heat zone in order to protect the plastic wrapping material for a package on which a label is being applied should it accidentally and unintentionally come in contact with the marginal portion of the heat conductive member.

A further object of the invention is to provide a label supporting member having a suitable heating element for heating the member to the desired degree to soften the adhesive on the heat sensitive label supported thereon and a timer control means for the heating element operable to intermittently secure operation of the heating element to heat the label supporting member during predetermined intervals of time determined by the timer control means. The timer means provided by the invention operates to control the period of time during which the label heating member is supplied with heat and operates in a manner to provide operation of the heating element during a limited time interval and to control the time interval between heating intervals for controlling the temperature to which the label heating member is heated with substantial accuracy or precision.

Adjustable means is provided on the timer for changing the timing period in a predetermined manner for varying the time period during which the label supporting heating member is heated by the heating element.

Another object of the invention is to provide a label supporting and heating member in the form of a substantially flat plate member having a plurality of openings about the marginal portion of an intermediate section of the label supporting and heating member with which the heating element is engaged so as to separate the label heating member into two heating zones having the marginal portion of the label supporting member heated to a lower temperature than the intermediate section thereof. The apertures in the label heating member provide for air passages through the member for use in creating sufficient suction in the aperture to hold the label against the outer surface of the label heating member.

Another object of the invention is to provide an adice FIG. 2 is a vertical longitudinal cross section through the label heating device;

FIG. 3 is a vertical fragmentary transverse cross section taken substantially along the line 33 of FIG. 2; and

FIG. 4 is a wiring diagram showing the electrical connections to the various parts of the label heating device.

A casing 2 supports and houses the various parts of the label heating device and has end walls 4, side walls 6, bottom wall 8 and top wall 10. An electric motor 12 is mounted on one end wall 4 and projects outwardly therefrom, as shown in FIGS. 1 and 2. The electric motor !12 carries a blower 14 mounted on the inner end thereof within the casing, as shown in FIGS. 2 and 3. The blower 14 has an air intake opening 16 communieating with the inside of the casing 2 and an exhaust manifold 18 extending through an aperture in one of the side walls 6, as shown in FIG. 3, for exhausting air from the casing 2 outwardly whenever the electric motor 12 operates the blower 14. The blower 14 and electric motor 12 are of a conventional form of construction Well known in the art.

The end of the casing 2 carrying the motor 12 on the end wall 4 is provided with a pair of supporting legs 20 at each bottom corner thereof, as shown in FIGS. 1 and 2. The free ends of the supporting legs 20 and the opposite end of the casing from that carrying supporting legs 20 mount suitable supporting feet 22 which may be in the form of suction cups or other suitable type of construction found desirable.

The top wall 10 of the casing is sl-idably and removably mounted over the side walls 6 and the end walls 4 by having a peripheral flange thereon engaging about the outer upper marginal portions of the side and end walls.

The top wall 10 is formed with a rectangular aperture 24 about which is mounted an upwardly extending tubular bracket 26. The tubular bracket 26 may be of the same rectangular shape as the aperture 24 so as to extend around and above the marginal portion of the cover '10 forming the aperture 24. The lower end portion of the tubular bracket 26 is formed with outwardly extending flanges superimposed on the outer surface of the cover 10 and suitably secured thereto by screws or other suitable means to rigidly attach the braclret 26 to the cover 10'.

A heat conductive means or member in the form of a plate 28- has the marginal portions on the underside detachably secured to flanges formed on the outer end of the tubular bracket 26 as shown in FIGS. 2 and 3. The central portion of the heat conductive member or label supporting plate 28 is termed with a recess for detachably receiving the heating unit 30* therein which forms a heating means for heating the heat conductive member 28. The heating unit 30 contains an electric resistance of conventional form assembled into a suitable container. The underside of the heat conductive member 28 has the marginal portions on the underside spaced outwardly beyond the recess receiving the heating unit 30 formed with recesses 32, as shown in FIGS. 2 land 3. The side margins of the plate '28 have a plurality of apertures 34 formed therein which extend from the outer label supporting surface 36 through the marginal portions of the plate for opening into the recess 32. These apertures separate the central portion of the outer label supporting surface 36 from the outer marginal portions of the heat conducting member 28 to reduce heat conduction between the intermediate portion of the member 28 and the outer marginal portions thereof and substantially define a portion of the margin between an inner heating zone which is heated to a higher temperature from an outer heating zone.

The heat conductive means or member 28 is formed of a suitable metal, such as aluminum, that will readily and rapidly conduct heat from the heating unit 30 to the outer label supporting surface 36. A pair of strips 38 are mounted one on each side edge of the heat conductive member 28 as shown in FIGS. 1 and 2, with the outer edges terminating flush with the outer label supporting surface 36 of the member 28. These strips 38 extend the full length of the sides of the heat conductive member 28 to operate therewith to provide a portion of the outer lower heat zone of the member 28 and the outer portion of the label supporting surface 36 thereof. The front and rear margins of the heat conductive means for the supporting plate 28 have the upper portions thereof recessed to receive a pair of strips 40, one strip being mounted in each recess, as shown in FIG. 3. The front strip 40 has its outer face formed to be flush with the outer label supporting surface .36 of the heat conducting member 28 for cooperation with the member 28 along the front margin thereof to form the outer lower heat zone about the marginal portions of the heat conducting member or label supporting plate 28.

The rear strip 40 is formed to have a portion extend outwardly beyond the outer label supporting surface 36 of the heat conductive member 28 to provide a shoulder and label positioning means 42. The pairs of strips 38 and 40 are formed of a low heat conductive material such as fiber sheet material. A label is indicated at 44 in FIG. 3, applied to the outer label supporting surface 36 of the heat conductive member 28. The label will be slidably moved so that one edge will engage the label positioning means or shoulder '42 for locating the label in position so the opposite edge will extend out to the front edge of the label supporting plate or heating member 28. The side edges of the label will also extend out to the side edges of the member 28 over the upper edges of the strips 38 to the outer sides thereof. The size of the heat conductive member 28 with its intermediate and marginal heating zones will he formed of a size to support labels 44 of a predetermined standard size, matched to the size of the heating plate 28 as further explained below. The type of labels 44 used in connection with this invention have one surface coated with an adhesive that is thermosensitive or thermally activated by heat to become sufliciently tacky to secure the label to the surface of a sheet or package to which it is to be attached.

A manual control switch 46 of conventional form is mounted on the end wall 4 opposite to that carrying the motor 12. A pilot light 48 of conventional form is also mounted on the same end wall with the switch 46, as shown in FIG. 1. The manual control switch 46 and the pilot light 48 operate in conjunction with one another so that when the manual control switch is moved to the on position it will connect the circuits of the motor 12 and the other electrical circuits within the casing 2 with a suitable source of supply for electric current when the label heating device is plugged in, in the manner hereinafter described in connection with the wiring diagram, FIG. 4.

A timer 50 is mounted on the inside of one side wall 6 and is used for controlling the heat of the heating unit or means 38 so as to control the heat transmitted to the heat conductive member 28. This timer is of any suitable conventional form which contains an electric circuit and contacts that may be included in the electric circuit for the heating unit 30 to open and close the circuit to the heating unit 30 at predetermined times and intervals for which the timer is set. The timer is of the form sometimes called a load regulator, since it operates on a thermostatic principle and thus gives a fairly accurate repetitive make and break action, sufiicient for present purposes, but not having the exact accuracy of certain other forms of timer. This timer unit has a manually rotatable shaft which extends through the side wall 6 of the casing 2 and carries a manually operable control dial 52 on the outer end for rotating the shaft to set the timer for the predetermined period during which the circuit to the heating unit 38 will be closed and the time during which it will be held open. The control dial 52 has a knob projecting outwardly therefrom for convenient manual engagement in rotating the shaft to set the timing period for the timer and an outwardly extending flange formed with a cut-out section 54 adapted to limit the rotation of the control dial in cooperation with the stop pin 56 mounted on the side 6 of the casing 2 and projecting outward-1y therefrom in position to lie within the cut-out section 5-4, as shown in FIG. 1. Suitable numerals or other indicia can be placed on the margin of the control dial 52 for indicating the adjustment of the dial for longer or shorter timing periods for connecting the heating unit 30 in circuit for heating the heat conductive member 28.

The electric circuit for the invention is illustrated in FIG. 4, in which the timer or timing means above referred to has the casing indicated by dotted outline with the timer construction indicated diagrammatically to illustrate how the electric circuits operate to produce a predetermined timing operation within the timer, and how they control the heating unit 30 for connecting the label heating device with a source of electrical supply. A suitable length of wire 58, as shown in FIG. 1, is extended from the casing 2 for connecting the device to a suitable source of power and for this purpose has a conventional form of connecting plug 60 at the free end adapted for insertion into the usual wall receptacle found in oflice, store and other buildings and connected to the usual city or commercial electrical supply found in most cities. The length of wire or cable 58 includes at least a pair of conductors 62 and 64 respectively, and if desired may include a third conductor to form a ground connection, only a portion of which is shown in FIG. 2. The conductors 62 and 64 are the usual insulated electric wire of a conventional form commonly used in connecting electrical equipment to a source of electrical supply. These conductors are extended to the manual control switch 46 where the conductor 64 is connected to one terminal of the switch 46 while the conductor 62 may be connected to a terminal on the body of the switch 46 in a conventional manner generally indicated in FIG. 2. A pair of conductors 66 and 68 respectively, have the end of the wire 66 connected to the opposite side of the switch 46 from the wire 64 and one end of the conductor 68 connected to the terminal with the conductor 62. The opposite ends of the conductors 66 and 68 are connected to opposite terminals of the electric motor 12, in the manner shown in FIG. 4. The pilot light 48 has conductors 70 and 72 connected with one of each secured to opposite terminals of the pilot light and the opposite ends of each connected to opposite sides of the circuit with the wire 70 connected to the terminal of the control switch 46 opposite to the conductor 64 and the end of the wire 72 connected in circuit to the terminal on the switch with the conductor 62. An electrical conductor 74 has one end connected to a terminal on the switch 46 with conductor 62 and the opposite end connected to the terminal 76 of the timing means 50. A conductor 78 has one end connected to the control switch 46 opposite to the terminal for the conductor 64 and the opposite end connected to a terminal 80 of the timer control mechanism '50. A conductor 82 has one end connected to the heating unit 30 and the opposite end connected to the terminal 84 of the timer unit 58. A conductor 86 has one end connected to the other terminal of the heating unit 30 and the opposite end connected to the terminal 76 of the control unit 50. It will be noted that two of the terminals shown on the timer unit 50 in FIG, 2 are indicated by the numeral 76 which corresponds with the terminals indicated in FIG. 4. These two terminals 76 are connected within the timer unit 50.

The wiring circuit in the timing unit includes a resistance or heater element 88 mounted on an elongated metallic strip 90 which may be a suitable conventional construction to cause the free end of the strip to move in one direction when it is not heated and to move in an opposite direction when heated. One end of the strip 90 is mounted on a pivot pin 92 and has a control arm 94 attached thereto adjacent to the pivot pin 92 which extends laterally therefrom. An adjusting member 96 has one end mounted on a support forming part of the casing for the timer '50 and the opposite end formed with a contact foot 98 engaged with an adjusting cam 100 mounted for rotation with a control shaft 102 carrying the manually operable control dial 52. An adjusting screw 104 is mounted in the adjusting member 06 for engagement with the free end of the control arm 94 to adjust the position of the control arm and the metallic strip 90 on the pivot pin 92 relative to the adjusting cam 100. The adjusting cam 100 has an eccentric surface on the outer periphery thereof with which the contact foot engages so that upon rotation of the control shaft 102 the cam will move the adjusting member 96 outwardly away from the control shaft 102, or provide for its movement toward the shaft 102 under the spring tension provided by the mounting of the adjusting member 96'.

The timer has a contact support 106 carrying a flexible contact arm 108 having a contact point 110 on the free end thereof. An armature 112 has one end connected by a spring to the contact support 106 for normally moving the free end toward a permanent magnet 114 mounted on a supporting bracket 116 carried by the casing for the timer 50. The supporting bracket 116 also carries a stationary contact arm having a contact point 118 thereon aligned with the contact point 110 which will close a circuit to be hereinafter described.

The free end of the contact arm 108 has an angular projection 120 formed thereon to extend through an opening in the armature 112 so that the armature 112 will engage the angular projection and move the flexible contact arm 108 with its contact point 110 away from the contact point 118 to open the circuit controlled thereby. The free end of the armature 112 is formed with a laterally extended end portion having an opening to receive the free end of the metallic strip 90. When the free end of the metallic strip 90 moves toward or from the stationary contact point 118, as shown diagrammatically in FIG. 4, it will provide for the movement of the armature 112 toward the permanent magnet 114 when the metallic strip 90 is unheated. When the metallic strip 90 is heated it will move the free end of the arm away from the stationary contact 118, engage the armature 112 at the free end and move it away from the permanent magnet 114. Thearmature 112 will in turn engage the angular projection 120 on the flexible contact arm 108 and move the contact point 110 out of engagement with the stationary contact point 118.

One terminal of the resistance or heater element 88 is connected to the terminal 76 within the timer casing as shown in FIG. 4. The opposite terminal of the heater element 88 is connected by a conductor 122 to the hexible contact arm 108. The stationary contact point 118 is connected by a conductor 124 to the terminal 80 of the control timer 50 and in turn connected by the conductor 78 to the terminal of the mmual control switch 46 opposite to that connected to the conductor 64.

The conductor 122 is also connected to the terminal 84 so that the circuit through the heating unit 30 is controlled by the contact points 110 and 118. The cir- 'cuit through the heating element 88 is also controlled by the contact points 110 and 118 with the heating element 88 and the heating unit 30 connected in parallel in the electrical circuit.

When it is desired to use the present invention for heating labels having thermO-sensitive adhesive on one face thereof, the operator will manually operate the manual control switch 46 to close the circuit from the power supply to the label heating device. The contact points 110 and 118 will normally be closed when the circuit is open due to the fact that the bi-metal strip '90 will have the free end move toward the stationary contact point 118 or the permanent magnet 114 so the armature 1'12 can be attracted to engage the free end with the permanent magnet 1114- and the resilient contact arm 108 operate to move the contact point 110 to engage the contact point 118.

As soon as the manual control switch 46 is closed the circuit will be closed from one side of the power supply through the conductors 78 and 124 to the contact points 118 and 110 respectively. The circuit will then extend from the contact point 110 through the wire 122 to the heating element 88 and through the conductor 8-2 to the heating unit 30. From the opposite terminals of these two heating units the circuit is closed through the conductors 74 and 86 to the opposite side of the power supply. The heating unit 30 will immediately heat up the unit and the heat conductive member 28 to heat the inner zone between the apertures 34 to a higher heat than the marginal portions of the heat conductive member 28. -At the same time the heating element for the resistance 88 will heat the metallic strip 90 and cause the free end to move outwardly away from the stationary contact 118 and the permanent magnet 114. When this metallic strip 90 has been heated for a predetermined length of time it will move the free end outwardly to engage the free end of the armature 112 and move it to engage the angular extension 120 on the flexible contact arm 108 and then disengage the contact 110 thereon from the stationary contact 118 for opening the circuit to both the heater element 88 and the heating unit 30. The heater element 88 and the metallic strip 90 will immediately start to cool and in a predetermined length of time will have the free end of the metallic strip 90 move toward the stationary contact 118 until the movable contact 110 engages the stationary contact 118 and again closes the circuit.

When the heat conductive member or label supporting plate 28 is heated it is then ready to have a label placed thereon with the adhesive surface on the side of the label opposite to that which engages the outer label supporting surface 36. The label is placed on the supporting surface 36 with one side engaged With the shoulder or label positioning means 42, as above described. The label is then allowed to rest upon the outer label supporting surface 36 until the adhesive is softened. Then a package of Wrapped material which may be wrapped with any suitable thin plastic sheet material may be placed on top of the label to have it adhere thereto. During this time in which the package with its sheet material covering is engaged with the label, the outer low heat zone of the label supporting surface 36 (that is, the marginal zone where the insulating strips 38 and 40 are located) will be heated to a lower temperature than the intermediate higher heat zone of the supporting surface 36 so that should the plastic film covering the package accidentally come in contact with some part of the marginal portion of the supporting plate 28, it will be protected against heating to a degree suflicient to form openings in the plastic covering by melting the thin film of plastic material.

The machine is intended for use with a predetermined standard size of label, and if a dilferent size of label is to be used, the heating plate 28 together with its heat insulating strips 38 and 40 is removed from the machine and replaced by a different heating plate assembly with diiferent dimensions matched to the size of the label. The matching is preferably as follows: The dimension of the label in one direction is greater than the distance from the shoulder 42 to the near edge of the insulating strip 40 on the opposite side of the heating plate, but less than the distance from such shoulder to the far edge of such insulating strip. In the other direction at right angles to the direction just mentioned, the dimension of the label is greater than the width of the exposed surface of the heating plate plus the width of one of the lateral insulating strips 38, but less than the exposed width of the heating plate plus the widths of both of the lateral insulating strips 38-. Thus Whenever the label is placed on the heating surface and moved by lateral finger pressure, if necessary, so that the edge of the label does not project outwardly beyond the outer edge of the insulating strip on any side, it is assured that the label fully covers the entire exposed area of the heating plate and thus any wrapping material on a package placed on top of the label can not make direct contact with the heating plate and can not be damaged thereby.

The present invention in providing the outer low temperature heating zone on the label supporting plate 28, provides a particularly advantageous construction wherein packages wrapped with thin plastic film of the type in wide commercial use may have heat sensitive labels adhered thereto without likelihood of damage to the package wrapping. This feature of the invention is aided by having the label positioning means or shoulder 42 for locating the label in centered relation on the outer label supporting surface 36 in a quick and efiicient manner so the label covers the intermediate highly heated portion or zone of the heat conductive member 28 for quickly heating the adhesive into a tacky condition for adhesion to a package wrapper applied thereto in the manner above described.

The timing unit 50 will open and close the circuit through the contacts 110 and 118 at periodic time intervals determined by the flexing of the metallic strip 90 and the connections between the free end of the metallic strip 90 and the free end of the armature 112 and the flexible contact am 108'. By adjusting manually operable control dial 52 on the outside of the casing, the control shaft 102 will rotate the adjusting cam 100 to move the adjusting member 96 and the control arm 94 to position the metallic strip 90 so that it will extend outwardly when heated to a greater or lesser extent and thereby control the period of time during which 'the contacts 110 and 118 are closed to close the circuit to the heating unit 30. In this way the timing unit 50 Will operate to control in a substantially accurate manner the heating of the heat conductive member or label support ing plate 28 to a desired temperature and by intermittently opening the circuit to the heating unit 30 it will maintain the temperature of the member 28 substantially uniform for efficiently softening the adhesive on labels to the desired extent for attaching the label to a package.

It will be understood that :as soon as the manual control switch 46 is closed, the pilot light 48 will be lighted to show that the circuit within the casing 2 is closed and at the same time the circuit to thernotor 12 will be closed to operate the blower. The blower sucks air into the casing through the apertures 34 and retains a label flat position upon the outer label supporting surface 36 by the suction thus created through the blower exhausting air trom the casing outwardly through the exhaust manifold 18 until a label is heated sufiiciently for attachment to a package. When the package is placed upon the label as above described, the label will adhere to the package when it can he lifted with the label from the label heating member 28 ready to have a new label applied to the label supporting member 28 for subsequent application to another package.

The provision of the inner and outer heating zones on the heat conductive member 28 and the outer label sup- 8- porting surface 36 thereof is obtained through the cooperation of the apertures 34 and the provision of the strips 38 and 40 so that thin plastic wrappings on packages Will not be heated to the point of causing them to open a hole in the film due to excessive heating while applying a label to the package. The control timer 50 independently controls the operation of the heating unit 30 by opening and closing the contacts 110 and 118 periodically, for predetermined times and intervals obtained by the adjustment of the manually operable control dial 52. The cut out section 54 in cooperation with the stop pin 56 controls the adjustment of the manually operable control dial 52 so that the high and low limits of the timing operation of the timer 50' will be controlled thereby. As a result, the temperature of the heating unit 3 will also be controlled in a substantially accurate man ner between high and low temperature limits to obtain a desired heating Of the heat conductive member 28. Adjustment of the manually operable control dial 52 rotates the control shaft 102 and the adjusting earn to move the adjusting member 96 to position the control arm 94 in the desired location for obtaining a desired temperature of the heating unit 30. The adjustment of the earn 100 will operate the control arm 194 to move the free end of the metallic strip 90 toward or from the contact point 118 which will control the period of time within which the free end of the metallic strip 90 takes to operate the armature 112 and the flexible contact arm 108 to disengage contact point 110 from the stationary contact 118.

The improved label heating device described above as provided by this invention obtains a construction that provides for the fast placement or location of a label on the label supporting member 28. The invention also obtains a longer motor life due to the lowered amount heat which might adversely affect the motor hearings or other parts of the motor. The lowered amount of heat (as compared with prior art devices) results partly from the more accurate control of the heat in the heating unit 30 in being alternately connected .and disconnected from the power supply, and more especially from the smaller effective heating area of the heating plate, therefore requiring less wattage to heat it, with consequently less heating of all adjacent parts, including the motor. The suc tion provided by the blower fan with the arrangement of the apertures 34- at the sides of the intermediate heating zone in the margin of the heat conductive member or label supporting plate 28 obtains a uniform and firm retention of a label against the outer label supporting surface 36.

It is seen from the foregoing disclosure that the objects and purposes of the invention are well fulfil-led. It is to be understood that the foregoing disclosure is given by way of illustrative example only, rather than by way of limitation, and that without departing from the invention, the details may be varied Within the scope of the appended claims.

What is claimed is:

1. A heating device of the class described, comprising a casing having one wall formed with an aperture, a tubular bracket mounted on and projecting outwardly from said one wall about said aperture to form an air passage, a heating plate mounted on and closing the outer end of said bracket formed with air inlet apertures communicating with the interior of said tubular bracket and easing, said heating plate having the outer face forming a label supporting and having a recessed marginal portion, low heat conducting members mounfed in said recessed marginal portion and cooperating with said heating plate to provide an intermediate high heat zone and a marginal low heat zone on said plate, label positioning means mounted on said heating plate for locating a label in predetermined relation thereon, electric heating means mounted on the inner face of said heating plate over said intermediate heat zoneportion thereof, an electric motor operated blower mounted in said casing for drawing air through the inlet apertures and bracket for exhaust outwardly from said casing adapted to hold a label engaged With the label support on the outer face of said heating plate over both of said heating zones thereof, and electric timing means mounted on said casing electrically connected with said electric heating means and a source of electric supply operable toclose the circuit to said electric heating means at predetermined time intervals for periodically heating said heating plate and open said circuit to prevent heating during the time intervals between those when the circuit is closed.

2]. A heating device fior thermio-activated adhesive coated labels, comprising a casing having one wall formed with an aperture, a heating plate mounted on said casing and closing said aperture rat the outer side of said casing formed with air inlet apertures communicating with the interior of said casing through said aperture, said heating plate having the outer surface forming a label support and having a recessed marginal portion, low heat conducting means mounted in said recessed marginal portion and cooperating with said heating plate to provide an intermediate high heat zone and a marginal low heat zone on said plate, label positioning means on said heating plate for locating a label of a size substantially equal to the size of said label supporting outer surface with the central portion over said high heat zone and marginal portions over said low heat zone, electric heating means mounted on the inner face of said heating plate over said intermediate heat zone portion thereof, and means for controlling the temperature of said heating means to maintain said heating plate at a substantially uniform temperature of a predetermined degree.

References Cited in the file of this patent UNITED STATES PATENTS 2,492,908 Von Hofe Dec. 27, 1949 2,644,151 Kruege-r June 30, 1953 2,753,430 Windberg July 3, 1956 2,766,810! Gibson Oct. 16, 1956 2,775,677 Schuetze Dec. 25, 1956 2,821,612 Schuetze Jan. 218, 1958 2,954,455 Bell Sept. 27, 1960 3,057,987 Klamp Oct. 9, 1962 

2. A HEATING DEVICE FOR THEMO-ACTIVATED ADHESIVE COATED LABELS, COMPRISING A CASING HAVING ONE WALL FORMED WITH AN APERTURE, A HEATING PLATE MOUNTED ON SAID CASING AND CLOSING SAID APERTURE AT THE OUTER SIDE OF SAID CASING FORMED WITH AIR INLET APERTURES COMMUNICATING WITH THE INTERIOR OF SAID CASING THROUGH SAID APERTURE, SAID HEATING PLATE HAVING THE OUTER SURFACE FORMING A LABELS SUPPORT AND HAVING A RECESSED MARGINAL PORTION, LOW HEAT CONDUCTING MEANS MOUNTED IN SAID RECESSED MARGINAL PORTION AND COOPERATING WITH SAID HEATING PLATE TO PROVIDE AN INTERMEDIATE HIGH HEAT ZONE AND A MARGINAL LOW HEAT ZONE ON SAID PLATE, LABEL POSITIONING MEANS ON SAID HEATING PLATE FOR LOCATING LABEL OF A SIZE SUBSTANTIALLY EQUAL TO THE SIZE OF SAID LABEL SUPPORTING OUTER SURFACE WITH THE CENTRAL PORTION OVER SAID HIGH HEAT ZONE AND MARGINAL PORTIONS OVER SAID LOW HEAT ZONE, ELECTRIC HEATING MEANS MOUNTED ON THE INNER FACE OF SAID HEATING PLATE OVER SAID INTERMEDIATE HEAT ZONE PORTION THEREJOF, AND MEANS FOR CONTROLLING THE TEMPERATURE OF SAID HEATING MEANS TO MAINTAIN SAID HEATING PLATE AT A SUBSTANTIALLY UNIFORM TEMPERATURE OF A PREDETERMINED DEGREE. 